The present invention relates to hearing aid systems, and more particularly to a hearing aid system that uses a tunnel, or a tube inserted into such a tunnel, made through soft tissue in order to connect the retro-auricular space behind the pinna to the ear canal. A hearing aid module is inserted into the tube or tunnel. The hearing aid module detects sound through a microphone positioned at the retro-auricular end of the module or inside the module, amplifies such sound, and directs the amplified sound through the tube or tunnel directly into the ear canal.
Traditionally, most hearing aids capture sound through a microphone that is located inside or on top of the pinna of the ear, and deliver an amplified and/or modified version of the sound signal into the user""s ear canal through a suitable electrical-to-audio transducer, e.g., a small speaker. Disadvantageously, the proximity of the microphone to the transducer poses the potential problem of feedback from the transducer to the microphone.
The solution in the past for eliminating feedback has been to occlude the ear canal via an ear mold such that the transducer is located distally to the occlusion, while the microphone is located proximally to the occlusion. Unfortunately, occlusion of the ear canal can create several disadvantages for the user, such as reverberation and physical discomfort, and is a major cause for non-use of traditional hearing aids by the hearing impaired.
In addition, it is desirable to make hearing aids less visible, as most users perceive the aid as imparting a negative stigma. Thus, hearing aids are continuously becoming smaller and have moved from behind the ear into the outer ear and into the canal of the ear.
It is known in the art to connect the retro-auricular space (space behind the pinna of the ear) to the ear canal via a hollow titanium tube that is permanently placed into soft tissue. See, e.g., U.S. Pat. No. 6,094,493, which patent is incorporated herein by reference. In one embodiment presented in the ""493 patent, an amplification hearing aid is connected to the proximal (retro-auricular) end of the tube, whereby the hearing aid is located behind the pinna of the ear and a transducer sends the amplified sound signal through the tube into the ear canal. This concept, which has been commercialized by Auric(copyright) Hearing Systems, Inc. of Charlotte, N.C. as the RetroX technology, allows a certain degree of amplification without feedback and without the need for occlusion of the ear canal. In another embodiment of the ""493 patent, the microphone, transducer, electrical and electronic components are installed in the tube. The existing technology suffers from infection and inflammation in the area of the tube, among other things.
Several concepts for implanting all or part of the hearing aid into the middle ear have been developed. Such approaches couple an amplified and processed version of the sound signal to structures of the middle ear mechanically, thereby reducing feedback without occlusion of the ear canal. Such systems also reduce or eliminate visibility of the hearing aid, and have the potential for improving user comfort. Disadvantageously, however, such middle-ear-coupled systems require, inter alia, a significant surgical procedure.
In U.S. Pat. No. 5,430,801, the use of a silicone tube is disclosed to direct the output of a conventional hearing aid, held in place behind the ear using an ear-hook or via a piercing through the cartilage of the pinna, into the ear canal. One embodiment disclosed in the ""801 patent contemplates placing the distal end of the tube in the middle ear to achieve better gain. However, such embodiment, like all middle-ear devices, involves a significant surgical procedure, and the risk of infection is much greater than a simple piercing of the soft tissue behind the ear. Further, the microphone associated with the hearing aid disclosed in the ""801 patent is held at the front of the pinna, either as part of the piercing or connected to the hearing aid through an earring-type coupler.
It is thus seen that what is needed is a hearing aid that is less visible, smaller, and which is positionable so that part or all of the hearing aid is recessed or implanted in the body so as to be largely invisible, and which does not occlude the ear canal. Moreover, what is needed is such a hidden, non-occluding hearing aid that can be readily removed for battery recharging or replacement. Furthermore, such a hearing aid should provide protection from infection and/or inflammation in the area of the aid.
The present invention addresses the above and other needs by providing a hearing aid module shaped so it can be inserted into a tunnel made through the soft tissue that connects the retro-auricular space with the ear canal.
The hearing aid module has the size and shape needed for it to fit in the soft tissue tunnel because it takes advantage of the availability of smaller batteries or other power sources, advances in microelectronic components, and advanced mechanical design capability. The hearing aid module contains a speaker, located on the distal part of the module so as to reside close to or inside the ear canal, a battery or other power source that powers the module, signal processing circuitry, and a microphone. The microphone is located at the proximal part of the module so as to reside close to or in the retro-auricular space behind the pinna, or may be located elsewhere within the module.
At least three major benefits are provided through use of the hearing aid module of the present invention: (1) visibility of the hearing aid is reduced or eliminated; (2) user comfort is increased because occlusion of the ear canal is unnecessary and because the volume of the hearing aid that typically sits behind the pinna is reduced or eliminated; and (3) by moving the transducer to the distal end of the module (so as to reside close to or in the ear canal when the module is inserted into the tunnel or tube), and by placing the microphone at or just outside the proximal end of the module (so as to reside behind the pinna of the ear) or within the module, feedback is greatly reduced and higher amplification of the sensed signal(s) is possible.
In one embodiment, a chronically implanted tube is first placed in the retro-auricular-space-to-ear-canal tunnel, and the hearing aid module of the present invention snugly fits inside the tube. In some embodiments, the tube is coated with a film or layer of steroid(s) or other drug(s) that, over time, minimize the risk of infection and/or inflammation.
In another embodiment, an acutely implanted tube, which may be coated with a steroid(s) or drug(s), is placed in the retro-auricular-space-to-ear-canal tunnel, and the hearing aid module of the present invention snugly fits inside the tube. After a suitable time, the tube may be removed and the hearing aid module, which may be coated with a steroid(s) or drug(s), placed directly into the tunnel.
In yet another embodiment, the hearing aid module, housed in a tube-like casing, is snugly inserted into the retro-auricular-space-to-ear-canal tunnel, with the speaker located near the ear canal, and the microphone located in the retro-auricular space behind the pinna or within the module.
The hearing aid module is preferably encapsulated or carried in an elongate flexible or rigid case or plug that is adapted to snugly slide into the implanted tube or retro-auricular-space-to-ear-canal tunnel. Such construction facilitates insertion and removal of the module into and from the tube or tunnel for the purpose of replacing or recharging the power source, or replacing the module with a new module.
In accordance with one aspect of the invention, users of the hearing aid module would preferably have at least two such modulesxe2x80x94one module which is inserted into the retro-auricular-space-to-ear-canal tunnel or tube, and which provides the hearing aid function of the invention; and at least one other module that serves as a spare. The power source of the spare module(s) may advantageously be replaced, replenished, or recharged when not in use.
In some embodiments, the signal processing circuitry processes signals received by the microphone so the sounds emitting from the speaker are compatible with the sounds traveling naturally through ear canal. The signal processing circuits may also contain circuitry that performs other electronic or signal processing functions, such as voice command recognition.
In additional embodiments, telemetry circuits and/or connector(s) allow communication with external devices, such as an external programmer, remote control unit, telephone land line or cellular network (e.g., a USTM network), computer, CD player, AM/FM and/or two way radio.